Functional and Morphological Outcomes after Trabeculectomy and Deep Sclerectomy-Results from a Monocentric Registry Study

The aim of this study was to compare the effectiveness of trabeculectomy (TE) and deep sclerectomy (DS) in lowering intraocular pressure (IOP) and thereby preserving visual field and peripapillary retinal nerve fiber layer (RNFL) tissue in primary open-angle glaucoma (POAG) cases. IOP, number of IOP-lowering medications, visual acuity, mean defect of standard automated perimetry, and mean peripapillary RNFL thickness were retrospectively collected and followed up for 3 years after surgery. TE was performed in 104 eyes and DS in 183 eyes. Age, gender, laterality, IOP, number of medications, visual acuity, perimetry mean defect, and peripapillary RNFL thickness were equally distributed at baseline. Mean IOP decreased from 23.8 ± 1.4 mmHg and 23.1 ± 0.4 mmHg to 13.4 ± 0.6 mmHg (p < 0.001) and 15.4 ± 0.7 mmHg (p = 0.001) in the TE and DS groups, respectively. Mean defect remained stable (TE: -11.5 ± 0.9 dB to -12.0 ± 1.1 (p = 0.090); DS: -10.5 ± 0.9 dB to -11.0 ± 1.0 dB (p = 0.302)), while mean peripapillary RNFL thickness showed further deterioration during follow-up (TE group: 64.4 ± 2.1 μm to 59.7 ± 3.5 μm (p < 0.001); DS group: 64.9 ± 1.9 μm to 58.4 ± 2.1 μm (p < 0.001)). Both TE and DS were comparably effective concerning postoperative reduction in IOP and medication. However, glaucoma disease further progressed during follow-up.

Postoperative RNFL-Changes after Successful Trabeculectomy: 2-Year Outcomes

BACKGROUND

The most important tool in glaucoma therapy is to lower the intraocular pressure to slow down the apoptosis of retinal ganglion cells. Trabeculectomy (TE) is considered the gold standard in glaucoma surgery. The aim of this study was to analyse the postoperative changes in retinal nerve fibre layer (RNFL) using optical coherence tomography (OCT) after TE.

MATERIAL AND METHODS

We examined 40 patients naïve to prior glaucoma surgery retrospectively, who received a TE for medically uncontrolled primary open-angle glaucoma (POAG). Intraocular pressure (IOP), IOP-lowering medication, mean deviation of perimetry, visual acuity and peripapillary RNFL-thickness using OCT were evaluated during the first 24 month after TE.

RESULTS

In total 40 eyes from 40 patients were treated with TE. Mean IOP decreased from 25.0 ± 0,9 to 13.9 ± 0.6 (p < 0.01), and the mean number of IOP-lowering eye drops from 3.3 ± 0.2 to 0.5 ± 0.2 (p < 0.01). Visual acuity and mean deviation in perimetry remained stable while mean global RNFL-thickness decreased from 67.8 ± 2.9 to 63.7 ± 2.9 (p < 0.01) and 63.4 ± 2.9 µm (p < 0.01) 12 and 24 months after TE.

CONCLUSION

The TE is an effective method to reduce the IOD and the amount of IOP-lowering medication. Nevertheless, a significant further loss in RNFL thickness was observed in the first 12 months after TE. Thus, RNFL changes seem to stabilise only after a protracted period.

PRESERFLO MicroShunt implantation versus trabeculectomy for primary open-angle glaucoma: a two-year follow-up study

BACKGROUND

To compare the intermediate-term efficacy of PRESERFLO (PF) MicroShunt implantation with trabeculectomy (TE) in patients with primary open-angle glaucoma, focusing on longitudinal changes of functional and structural parameters.

METHODS

This retrospective comparative study included 104 eyes of 104 patients who underwent TE and 83 eyes of 83 patients that underwent PF implantation between January 2019 and December 2020, with a minimum follow-up of two years. Baseline and postoperative intraocular pressure (IOP), number of IOP-lowering medications, visual field mean defect (MD) and peripapillary retinal nerve fibre layer (RNFL) thickness measured using optical coherence tomography were assessed and compared between groups.

RESULTS

Baseline characteristics (age, sex, IOP, number of IOP-lowering medications, MD, RNFL thickness) were comparable between the two groups (all P > 0.05). During the two-year of follow-up, mean IOP decreased from 24.09 ± 1.15 mmHg and 21.67 ± 0.77 mmHg to 11.37 ± 1.13 mmHg (P < 0.001) and 15.50 ± 1.54 mmHg (P = 0.028), and the mean number of IOP-lowering medications decreased from 3.25 ± 0.14 and 3.51 ± 0.14 to 0.53 ± 0.14 (P < 0.001) and 1.06 ± 0.43 (P < 0.001) in the TE and PF groups, respectively. MD remained stable [- 11.54 ± 0.93 dB and - 11.17 ± 1.66 to - 10.67 ± 0.91 dB (P = 0.226) and - 10.40 ± 4.75 dB (P = 0.628) in the TE and PF groups, respectively] but RNFL thickness decreased continuously during follow-up [62.79 ± 1.94 µm and 62.62 ± 2.05 µm to 57.41 ± 1.81 µm (P < 0.001) and 60.22 ± 1.98 µm (P = 0.182) in the TE and PF groups, respectively].

CONCLUSION

PF implantation is comparably effective in the intermediate term in lowering IOP and reducing the use of IOP-lowering medications over a two-year follow-up period. Although visual field defects were stable, RNFL continued to decrease during postoperative follow-up.

Microbiome and Retinal Vascular Diseases

The gut microbiome consists of more than a thousand different microbes and their associated genes and microbial metabolites. It influences various host metabolic pathways and is therefore important for homeostasis. In recent years, its influence on health and disease has been extensively researched. Dysbiosis, or imbalance in the gut microbiome, is associated with several diseases. Consequent chronic inflammation may lead to or promote inflammatory bowel disease, obesity, diabetes mellitus, atherosclerosis, alcoholic and non-alcoholic liver disease, cirrhosis, hepatocellular carcinoma, and other diseases. The pathogenesis of the three most common retinal vascular diseases, diabetic retinopathy, retinal vein occlusion, and retinal artery occlusion, may also be influenced by an altered microbiome and associated risk factors such as diabetes mellitus, atherosclerosis, hypertension, and obesity. Direct cause-effect relationships remain less well understood. A potential prevention or treatment modality for these diseases could be targeting and modulating the individual's gut microbiome.

Stage specific glaucomatous changes of the macula recorded using spectral domain optical coherence tomography

BACKGROUND

This study aimed to compare the thickness of different macular retinal layers in glaucomatous eyes and healthy controls, and evaluate the diagnostic performance of spectral domain optical coherence tomography (SD-OCT) parameters.

METHODS

In this cross-sectional comparative study, 48 glaucomatous eyes and 44 healthy controls were included. The thickness of the total retina and all retinal layers were obtained using the Early Treatment Diagnostic Retinopathy Study (ETDRS) grid. The minimal and average values of outer and inner ETDRS-rings were calculated. The diagnostic performance for detection of glaucoma was evaluated using the area under the receiver operating characteristic curve (AUC).

RESULTS

The thickness of the total retina, ganglion cell layer (GCL), and inner-plexiform layer (IPL) was significantly thinner in glaucomatous eyes in all sectors except the center (all p<0.05). The thickness of retinal nerve fiber layer (RNFL) was significantly thinner in the glaucoma group except in the center, nasal inner, and temporal outer sectors (all p<0.05). Layer thinning advanced with glaucoma severity. The minimal outer GCL thickness showed the highest AUC value for discrimination between glaucomatous eyes and healthy controls(0.955). The minimal outer IPL showed the highest AUC value for discriminating early-stage glaucomatous eyes from healthy controls (0.938).

CONCLUSIONS

Glaucomatous eyes were found to have significant thinning in the macular region. GCL and IPL showed high ability to discriminate glaucomatous and early-stage glaucomatous eyes from controls. Applying the minimal value to the ETDRS grid has the potential to provide good diagnostic abilities in glaucoma screening.

Different responses of the MIO‑M1 Mueller cell line to angiotensin II under hyperglycemic or hypoxic conditions

Members of the renin-angiotensin aldosterone system (RAAS) are expressed by various retinal tissues including Mueller glial cells. As the RAAS is hypothesized to play an important role in the pathogenesis of diseases that threaten vision, such as diabetic macular edema or retinal vein occlusion, the possible changes induced by exposure of the human cell line MIO-M1, an established model of Mueller cells, to angiotensin II or aldosterone for 6 h under hypoxic and/or hyperglycemic conditions were investigated. The mRNA expression levels of the members of the RAAS were assessed by reverse transcription-quantitative PCR, and the secretion of cytokines was assessed by ELISA. Under hyperglycemic conditions, the mRNA expression levels of the angiotensin-converting enzyme 2 (ACE2), angiotensin II receptors, AT1 and AT2, and the receptor of angiotensin (1-7) MAS1 were significantly higher after exposure to angiotensin II, and the expression of ACE2, AT2, and IL-6 (a marker of inflammation) was significantly increased after treatment with aldosterone; the expression of the other targets investigated remained unchanged. Significantly more IL-6 was secreted by MIO-M1 cells exposed to hyperglycemia and angiotensin. When cells were cultured in a hypoxic environment, additional treatment with aldosterone significantly increased the mRNA expression levels of ACE, but significantly more ACE2 mRNA was expressed in the presence of angiotensin II. Under hypoxic plus hyperglycemic conditions, significantly less ACE but more AT2 was expressed after treatment with angiotensin II, which also led to strongly elevated expression of IL-6. The mRNA expression levels of the angiogenic growth factor VEGF-A and secretion of the encoded protein were notably increased under hypoxic and hypoxic plus hyperglycemic conditions, irrespective of additional treatment with angiotensin II or aldosterone. These findings suggest that angiotensin II induces a pro-inflammatory response in MIO-M1 cells under hyperglycemic conditions despite activation of the counteracting ACE2/MAS1 signaling cascade. However, hypoxia results in an increased expression of angiogenic VEGF-A by these cells, which is not altered by angiotensin II or aldosterone.

The need of rebubbling in case of small graft detachments after Descemet Membrane Endothelial Keratoplasty (DMEK)

Purpose

To investigate the need of rebubbling for small graft detachments after Descemet Membrane Endothelial Keratoplasty (DMEK).

Methods

In this retrospective study we evaluated 111 eyes from 111 patients that showed graft detachment after DMEK surgery and have achieved graft adherence by injection of air or 20% sulfur hexafluoride (SF6) to the anterior chamber (rebubbling group; n = 57) or by spontaneous adherence without intervention (control group; n = 54) at final examination. Subgroups in terms of the maximum height and in terms of the detachment area in relation to graft area were formed. Outcome measures were the increase in best-corrected visual acuity (BCVA) and the decrease in central corneal thickness (CCT) from the measurement before DMEK to six months after surgery and postoperative endothelial cell density.

Results

BCVA increased in the rebubbling group and the control group, the difference being 0.22 logMAR, p = 0.048. For eyes with a maximum height less than 500  µm, the increase of BCVA was 0.39 ± 0,36 logMAR in the control group and 0.62 ± 0,53 logMAR in the rebubbling group, p = 0.045. There was no difference of statistical significance of BCVA between both groups regarding the detachment area of less than 20% in relation to graft area. The mean decrease in CCT and postoperative endothelial cell density showed no significant difference between the rebubbling group and the control group.

Conclusion

Compared to spontaneous graft adherence, a rebubbling shows no beneficial effect on the clinical outcome for small detached DMEK grafts. Rebubbling does not decrease postoperative endothelial cell density.

[Therapy of malignant glaucoma]

Malignant glaucoma is a rare and complex eye disease but the exact cause has not yet been clarified with certainty. Malignant glaucoma can be treated with medication or by means of laser surgery or open incisional surgery. In this article the possible procedures for the treatment of malignant glaucoma (medicinal and surgical) are presented together and justifications for the procedures described are given.

Descemet membrane endothelial keratoplasty (DMEK) improves vision-related quality of life

Purpose

To evaluate vision-related quality of life (VRQL) before and after Descemet membrane endothelial keratoplasty (DMEK).

Methods

The study was conducted in patients with Fuchs endothelial dystrophy or pseudophakic bullous keratopathy undergoing DMEK alone or in combination with cataract surgery (triple-DMEK) between August 2019 and March 2020 at the University of Leipzig Medical Center. Best-corrected visual acuity (BCVA) was measured. Visual acuity factor (VAF) and glare factor (GF) scores were calculated using the Visual Function and Corneal Health Status Instrument questionnaire answered by patients before surgery and 6 months thereafter. Subgroup analyses were performed for DMEK versus triple-DMEK, and for first versus second eyes, in addition to correlation analyses of scores with preoperative BCVA.

Results

Forty-six patients were included in this analysis. VAF score improved from 0.68 ± 0.54 to 0.02 ± 0.57 (P < 0.0001) and GF score improved from 0.53 ± 0.43 to -0.11 ± 0.39 (P < 0.0001) during follow-up. Both scores improved without significant differences after surgery in the first and in the fellow eye (P < 0.0001) and after DMEK and triple-DMEK (P < 0.0001). The improvement of scores did not correlate with preoperative BCVA (r = 0.06, P = 0.68 for VAF; r =  -0.09, P = 0.54 for GF).

Conclusion

VRQL improves similarly after DMEK and triple-DMEK and between first and second operated eye. The extent of improvement is independent of the preoperative BCVA. The results of this study can be useful when planning DMEK by enabling a prediction of anticipated VRQL gain.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00417-022-05711-9.

Netzhaut-Glaskörperchirurgie bei Glaukom

Abstract (deutsch): Die Glaukome gehen mit einem Untergang von retinalen Ganglienzellen und deren Axonen einher, welche sich vornehmlich in der Netzhaut befinden. Die Vitreoretinale- und die Glaukomchirurgie überschneiden sich bei bestimmten Krankheitsbildern in einem nicht geringen Ausmaß. Ziel des vorliegenden Übersichtsartikels ist es diese Krankheitsbilder darzustellen und Behandlungsstrategien und die jeweiligen Wirkungsweisen gesammelt aufzuzeigen. Im Rahmen des vorliegenden Artikels werden die Themen malignes Glaukom / aqueous misdirection syndrome, Netzhautchirurgie bei Aderhautamotio und expulsiver Aderhautblutung, postoperative Blebitis und Endophthalmitis nach Glaukomoperation und Vitrektomie nach Glaukomoperationen zusammen beschrieben und die bestehenden Therapiepfade beim Management von auftretenden Komplikationen aufgezeigt. Insgesamt sind die Bereiche Glaukom- und Netzhaut-Glaskörperchirurgie eng miteinander verbunden. Kollegen beider Subspezialitäten sollten Kenntnisse über diese sie beide betreffenden Krankheitsbilder haben. Abstract (englisch): Glaucoma is associated with the demise of retinal ganglion cells and their axons, which are primarily located in the retina. Vitreiretinal and glaucoma surgery overlap to a not inconsiderable extent in certain diseases. The aim of this overview article is to present these diseases and to highlight treatment strategies and the respective modes of action in a collective manner. Within the scope of this article, the topics of malignant glaucoma / aqueous misdirection syndrome, retinal surgery for choroidal detachment and expulsive choroidal hemorrhage, postoperative blebitis and endophthalmitis after glaucoma surgery and vitrectomy after glaucoma surgery are described together and the existing therapeutic paths for the management of complications are shown. The areas of glaucoma and vitreoretinal surgery are tightly linked. Colleagues from both subspecialties should be familiar with a certain overview of diseases concerning both subject areas.

Microvascular and Structural Alterations of the Macula in Early to Moderate Glaucoma: An Optical Coherence Tomography-Angiography Study

In glaucoma, macular optical coherence tomography (OCT) typically shows a thinning of the three inner segments and OCT-angiography (OCTA) a reduction of the vascular density (VD). It is still unclear if glaucoma directly affects macular VD. This retrospective study included 31 glaucoma patients of early and moderate stage (GS1, GS2, Mills et al.) and 39 healthy individuals. Macular segments' thickness and superficial and deep plexus vascular density (VD) were obtained using spectral-domain OCT and OCTA, respectively. One-way analysis of variance (ANOVA) was used to compare healthy controls and glaucoma patients according to their glaucoma stage. Using correlation analyses, the association between glaucoma and either OCT or OCTA parameters was evaluated. A glaucoma stage-stratified linear regression analysis was then performed. Inner macular segment and whole retinal thickness were reduced in GS1 and GS2 patients compared to healthy controls (e.g., ganglion cell layer GCL: controls: 47.9 ± 7.4, GS1: 45.8 ± 5.1, GS2: 30.6 ± 9.4, ANOVA: p < 0.0001). Regarding OCTA-parameters, the VD of both segmentation levels was reduced in glaucoma patients, particularly when comparing GS2 patients with controls (superficial plexus: p = 0.004) and GS2 with GS1 (p = 0.0008). Linear regression revealed an association between these parameters and the presence of glaucoma (for superior plexus: R2 = 0.059, p = 0.043). Finally, a correlation between macular segment thickness and VD was observed, but with a strength increasing with glaucoma severity (GCL and superior plexus VD: controls: R2 = 0.23, GS1 R2 = 0.40, GS2 R2 = 0.76). Despite the glaucoma-independent correlation between macular segment thickness and VD, disease severity strengthens this correlation. This consideration suggests that glaucoma directly influences OCT and OCTA parameters individually.

Implantation of XEN After Failed Trabeculectomy: an Efficient Therapy?

BACKGROUND

Trabeculectomy (TE) has been the standard procedure in glaucoma surgery for a long time. This study examined the efficacy and safety profile of XEN45 Gel Stent (XEN) after failed and/or scarred trabeculectomy.

MATERIAL AND METHODS

We analysed all files of patients, who received a XEN after insufficient TE and examined changes in intraocular pressure (IOP), IOP-lowering medication, best corrected visual acuity, visual field tests as well as the intra- and postoperative complications recorded within a 12-month follow-up period.

RESULTS

31 eyes of 28 patients were analysed in our study (mean age: 66,2 ± 13,4 years; 39% female; 48% right eye; mean follow-up after TE: 70,3 ± 64,9 months). The mean IOP decreased from 23,5 ± 6,5 to 18,0 ± 5,3 mmHg (- 23,5% compared to baseline-IOP; p = 0,01) while the mean IOP-lowering medication could be reduced from 2,8 ± 1,1 to 1,1 ± 1,5 (p < 0,01) 12 months after XEN-implantation. The mean visual acuity did not change significantly (pre-op: 0,5 ± 0,6 logMAR; 12 months post-op: 0,5 ± 0,6 logMAR). The most common complications postoperatively were choroideal detachment due to postoperative hypotony in 4 eyes (13%), a needling procedure in 9 eyes (29%), a Re-XEN-Implantation in 4 eyes (13%), an open revision of the conjunctiva in 3 eyes (10%), and a Re-TE in 1 eye (3%) as well as an Ahmed-Valve implantation in 2 eyes (6%). Overall, neither needling procedure nor further glaucoma surgery was necessary in 19 eyes (61%). In 10 of 22 evaluable eyes (45%) an IOP reduction of > 20% was achieved 12 months after XEN implantation.

CONCLUSION

XEN could be an effective method to reduce IOP after failed TE. The rate of complications seems to be low and the rate of needling procedures and/or revisions is acceptable.

Neuroprotective effects of glial mediators in interactions between retinal neurons and Müller cells

Progressive retinal ganglion cell (RGC) loss underlies a number of retinal neurodegenerative disorders, which may lead to permanent vision loss. However, secreted neuroprotective factors, such as PEDF, VEGF and IL-6, which are produced by Müller cells, have been shown to promote RGC survival. Assuming that the communication of RGCs with Müller cells involves a release of glioactive substances we sought to determine whether retinal neurons are able to modulate expression levels of Müller cell-derived PEDF, VEGF and IL-6. We demonstrate elevated mRNA levels of these factors in Müller cells in co-cultures with RGCs or R28 cells when compared to homotypic Müller cell cultures. Furthermore, R28 cells were more protected from apoptosis when co-cultured with Müller cells. IL-6 and VEGF were upregulated in Müller cells under hypoxia. Both cytokines, as well as PEDF, induced an altered neuronal expression of members of the Bcl-2 family, which are central molecules in the regulation of apoptosis. These results suggest that in retinal ischemia, via own secreted mediators, RGCs can resist a potential demise by stimulating Müller cells to increase production of neuroprotective factors, which counteract RGC apoptosis.

Foveal regeneration after resolution of cystoid macular edema without and with internal limiting membrane detachment: presumed role of glial cells for foveal structure stabilization

AIM

To document with spectral-domain optical coherence tomography the morphological regeneration of the fovea after resolution of cystoid macular edema (CME) without and with internal limiting membrane (ILM) detachment and to discuss the presumed role of the glial scaffold for foveal structure stabilization.

METHODS

A retrospective case series of 38 eyes of 35 patients is described. Of these, 17 eyes of 16 patients displayed foveal regeneration after resolution of CME, and 6 eyes of 6 patients displayed CME with ILM detachment. Eleven eyes of 9 patients displayed other kinds of foveal and retinal disorders associated with ILM detachment.

RESULTS

The pattern of edematous cyst distribution, with or without a large cyst in the foveola and preferred location of cysts in the inner nuclear layer or Henle fiber layer (HFL), may vary between different eyes with CME or in one eye during different CME episodes. Large cysts in the foveola may be associated with a tractional elevation of the inner foveal layers and the formation of a foveoschisis in the HFL. Edematous cysts are usually not formed in the ganglion cell layer. Eyes with CME and ILM detachment display a schisis between the detached ILM and nerve fiber layer (NFL) which is traversed by Müller cell trunks. ILM detachment was also found in single eyes with myopic traction maculopathy, macular pucker, full-thickness macular holes, outer lamellar holes, and glaucomatous parapapillary retinoschisis, and in 3 eyes with Müller cell sheen dystrophy (MCSD). As observed in eyes with MCSD, cellophane maculopathy, and macular pucker, respectively, fundus light reflections can be caused by different highly reflective membranes or layers: the thickened and tightened ILM which may or may not be detached from the NFL, the NFL, or idiopathic epiretinal membranes. In eyes with short single or multiple CME episodes, the central fovea regenerated either completely, which included the disappearance of irregularities of the photoreceptor layer lines and the reformation of a fovea externa, or with remaining irregularities of the photoreceptor layer lines.

CONCLUSION

The examples of a complete regeneration of the foveal morphology after transient CME show that the fovea may withstand even large tractional deformations and has a conspicuous capacity of structural regeneration as long as no cell degeneration occurs. It is suggested that the regenerative capacity depends on the integrity of the threedimensional glial scaffold for foveal structure stabilization composed of Müller cell and astrocyte processes. The glial scaffold may also maintain the retinal structure after loss of most retinal neurons as in late-stage MCSD.

General health of patients with diabetic macular edema-The LIPSIA study

Purpose

Cardiovascular risk factors such as hypertension or dyslipidemia can influence the incidence and progression of diabetic retinopathy (DR) and diabetic macular edema (DME). The aim of this study is to describe the comorbidities in patients with DME.

Methods

Prospective, monocentric observational study. Patients presenting for the treatment of DME received laboratory and clinical examinations including 24-hour blood pressure measurement.

Results

Seventy-five consecutive patients were included in the study. The mean age was 61.0 ± 14.5 years, and 83% had type 2 diabetes. The mean body mass index (BMI) was 32.8 ± 6.0 kg/m². Overweight (BMI ≥ 25 kg/m²) was present in 92% of all patients. HbA1c values were > 7.0% in 57%. Although 87% of the patients already received antihypertensive therapy, the blood pressure (BP) of 82% was still above the recommended target values of systolic < 140 mmHg and diastolic < 80 mmHg. An insufficient nocturnal fall of the systolic BP (< 10%, non-dipping or reverse dipping) was observed in 62%. In 83% of the patients the glomerular filtration rate was ≤ 90 ml/min/1.73m². Despite 65% of the cohort already receiving lipid-lowering therapy, LDL cholesterol was above the target value of 1.4 mmol/l in 93%. All patients had at least one cardiovascular risk factor in addition to diabetes (overweight, hypertension, insufficient nocturnal BP fall, dyslipidemia, or renal dysfunction) and 86% had ≥ 3 risk factors.

Conclusion

DME patients are characterized by highly prevalent cardiovascular risk factors that are poorly controlled. These comorbidities reduce the prognosis and negatively influence existing DR and DME. The data reveal an important opportunity for improving patient care by interaction of the ophthalmologist with the general practitioner and internal specialists for the detection and treatment of these conditions.

Müller cells and astrocytes in tractional macular disorders

Tractional deformations of the fovea mainly arise from an anomalous posterior vitreous detachment and contraction of epiretinal membranes, and also occur in eyes with cystoid macular edema or high myopia. Traction to the fovea may cause partial- and full-thickness macular defects. Partial-thickness defects are foveal pseudocysts, macular pseudoholes, and tractional, degenerative, and outer lamellar holes. The morphology of the foveal defects can be partly explained by the shape of Müller cells and the location of tissue layer interfaces of low mechanical stability. Because Müller cells and astrocytes provide the structural scaffold of the fovea, they are active players in mediating tractional alterations of the fovea, in protecting the fovea from such alterations, and in the regeneration of the foveal structure. Tractional and degenerative lamellar holes are characterized by a disruption of the Müller cell cone in the foveola. After detachment or disruption of the cone, Müller cells of the foveal walls support the structural stability of the foveal center. After tractional elevation of the inner layers of the foveal walls, possibly resulting in foveoschisis, Müller cells transmit tractional forces from the inner to the outer retina leading to central photoreceptor layer defects and a detachment of the neuroretina from the retinal pigment epithelium. This mechanism plays a role in the widening of outer lameller and full-thickness macular holes, and contributes to visual impairment in eyes with macular disorders caused by conractile epiretinal membranes. Müller cells of the foveal walls may seal holes in the outer fovea and mediate the regeneration of the fovea after closure of full-thickness holes. The latter is mediated by the formation of temporary glial scars whereas persistent glial scars impede regular foveal regeneration. Further research is required to improve our understanding of the roles of glial cells in the pathogenesis and healing of tractional macular disorders.

Foveal configurations with disappearance of the foveal pit in eyes with macular pucker: Presumed role of Müller cells in the formation of foveal herniation

Many eyes with macular pucker are characterized by a centripetal displacement of the inner foveal layers which may result in a disappearance of the foveal pit. In this retrospective case series of 90 eyes with macular pucker of 90 patients, we describe using spectral-domain optical coherence tomography different foveal configurations with ectopic inner foveal layers, document the relationship between posterior vitreous detachment (PVD) and idiopathic epiretinal membrane (ERM) formation and spontaneous and postoperative morphological alterations of the fovea, and propose an active role of Müller cells in the development of foveal herniation. We found that ERM were formed during or after partial perifoveal PVD, or after foveal deformations caused by tissue edema. The ERM-mediated centripetal displacement of the inner foveal layers and in various eyes anterior hyaloidal traction caused a disappearance of the foveal pit and an anterior stretching of the foveola with a thickening of the central outer nuclear layer (ONL). After the edges of the thickened inner layers of the foveal walls moved together, continuous centripetal displacement of the inner foveal layers generated a bulge of the fovea towards the vitreous (foveal herniation). Macular pseudoholes with a herniation of the inner foveal layers show that the outer layer of the protruding foveal walls is the outer plexiform layer (OPL). If the ERM covered the foveal walls and parafova, but not the foveola, the inner layers of the foveal walls were not fully centripetally displaced and the foveal pit was present. The visual acuity of eyes with ectopic inner foveal layers was inversely correlated with the thickness of the foveal center. Spontaneous morphological alterations after disappearance of the foveal pit may include the development of cystoid macular edema or additional thickening of the foveal tissue and foveal herniation. The foveal configuration with ectopic inner layers of the foveal walls and a thick central ONL persisted over longer postoperative time periods. The data show that the centripetal displacement of the inner foveal layers in eyes with macular pucker, which results in a disappearance of the foveal pit, may also generate foveal herniation which is suggested to be caused by contraction of Müller cell processes in the OPL. The centripetal displacement of the inner foveal layers and the formation of foveal herniation are suggested to reverse the foveal pit formation during development.

Functional Monitoring after Trabeculectomy or XEN Microstent Implantation Using Spectral Domain Optical Coherence Tomography and Visual Field Indices-A Retrospective Comparative Cohort Study

Simple Summary

Primary open-angle glaucoma leads to a loss of retinal ganglion cells and a reduction in the retinal nerve fiber layer thickness, consequently leading to the development and growth of visual field defects. In its final stages, this results in visual loss and irreversible blindness if not treated adequately. A reduction in the intraocular pressure by means of medication and/or surgery is the only known treatment option for slowing, or at best, arresting disease progression. This study demonstrates that trabeculectomy and XEN microstent implantation are nearly equally effective techniques for reducing intraocular pressure and stabilizing visual acuity and pre-developed visual field defects over a follow-up period of 24 months after surgery. However, further analysis using spectral domain optical coherence tomography revealed that disease progression occurs in terms of further retinal nerve fiber layer loss after both trabeculectomy and XEN microstent implantation.

Abstract

The aim of this study was to compare the efficacy of trabeculectomy (TE), single XEN microstent implantation (solo XEN) or combined XEN implantation and cataract surgery (combined XEN) in primary open-angle glaucoma cases, naïve to prior surgical treatment, using a monocentric retrospective comparative cohort study. Intraocular pressure (IOP) and the number of IOP-lowering drugs (Meds) were monitored during the first 24 months after surgery. Further disease progression was monitored using peripapillary retinal nerve fiber layer (RNFL) thickness examinations using spectral domain optical coherence tomography (OCT) as well as visual acuity (VA) and visual field (VF) tests. In the TE group (52 eyes), the mean IOP decreased from 24.9 ± 5.9 to 13.9 ± 4.2 mmHg (p < 0.001) and Meds decreased from 3.2 ± 1.2 to 0.5 ± 1.1 (p < 0.001). In the solo XEN (38 eyes) and the combined XEN groups, the mean IOP decreased from 24.1 ± 4.7 to 15.7 ± 3.0 mmHg (p < 0.001) and 25.4 ± 5.6 to 14.7 ± 3.2 mmHg (p < 0.001), while Meds decreased from 3.3 ± 0.8 to 0.8 ± 1.2 (p < 0.001) and 2.7 ± 1.2 to 0.4 ± 1.0 (p < 0.001), respectively. The VF and VA indices showed no sign of further deterioration, the RNFL thickness further decreased in all treatment groups after surgery. TE and XEN led to comparable reductions in IOP and Meds. Although the VA and VF indices remained unaltered, the RNFL thickness continuously decreased in all treatment groups during the 24-month follow-up.

Degenerative lamellar macular holes: tractional development and morphological alterations

Purpose

The development of degenerative lamellar macular holes (DLH) is largely unclear. This study was aimed at documenting with spectral-domain optical coherence tomography the tractional development and morphological alterations of DLH.

Methods

A retrospective case series of 44 eyes of 44 patients is described.

Results

The development of DLH is preceded for months or years by tractional deformations of the fovea due to the action of contractile epiretinal membranes (ERM) and/or the partially detached posterior hyaloid, or by cystoid macular edema (CME). DLH may develop after a tractional stretching and thickening of the foveal center, from a foveal pseudocyst, after a detachment of the foveola from the retinal pigment epithelium, a disruption of the foveal structure due to CME, and after surgical treatment of tractional lamellar or full-thickness macular holes (FTMH). The foveal configuration of a DLH can be spontaneously reestablished after short transient episodes of CME and a small FTMH. A DLH can evolve to a FTMH by traction of an ERM. Surgical treatment of a DLH may result in an irregular regeneration of the foveal center without photoreceptors.

Conclusions

Tractional forces play an important role in the development of DLH and in the further evolution to FTMH. It is suggested that a DLH is the result of a retinal wound repair process after a tractional disruption of the Müller cell cone and a degeneration of Henle fibers, to prevent a further increase in the degenerative cavitations.

Pigment Epithelium-Derived Factor (PEDF) Receptors Are Involved in Survival of Retinal Neurons

The demise of retinal ganglion cells (RGCs) is characteristic of diseases of the retina such as glaucoma and diabetic or ischemic retinopathies. Pigment epithelium-derived factor (PEDF) is a multifunctional secreted protein that mediates neuroprotection and inhibition of angiogenesis in the retina. We have studied expression and regulation of two of several receptors for PEDF, patatin-like phospholipase 2 gene product/PEDF-R and laminin receptor (LR), in serum-starved RGC under normoxia and hypoxia and investigated their involvement in the survival of retinal neuronal cells. We show that PEDF-R and LR are co-expressed in RGC and R28 retinal precursor cells. Expression of both receptors was enhanced in the presence of complex secretions from retinal glial (Müller) cells and upregulated by VEGF and under hypoxic conditions. PEDF-R- and LR-knocked-down cells demonstrated a markedly attenuated expression of anti-apoptotic Bcl-2 family members (Bcl-2, Bcl-xL) and neuroprotective mediators (PEDF, VEGF, BDNF) suggesting that both PEDF-R and LR mediate pro-survival effects of PEDF on RGC. While this study does not provide evidence for a differential survival-promoting influence of either PEDF-R or LR, it nevertheless highlights the importance of both PEDF receptors for the viability of retinal neurons.

Outcome of a single XEN microstent implant for glaucoma patients with different types of glaucoma

BACKGROUND

The aim of this retrospective study was to compare the efficacy and safety profile of a single XEN-microstent in different types of primary and secondary open angle glaucoma.

METHODS

A single XEN microstent was implanted in patients with primary open-angle glaucoma (POAG), normal-tension glaucoma (NTG), pseudoexfoliation glaucoma (PEX) and secondary glaucoma (Sec.Gl). The intraocular pressure (IOP), the active substances of the applied IOP-lowering drugs, the best corrected visual acuity (BCVA) and the mean deviation (MD) of the perimetry were measured at baseline and at regular follow-ups, scheduled at 2 days and 1, 3, 6 and 12 months after surgery.

RESULTS

153 eyes were included in this analysis. 113 eyes were affected by POAG (74%), 5 eyes by NTG (3%), 22 eyes by PEX (14%) and 13 eyes by Sec. Gl (9%). Mean IOP decreased in all treatment groups during the 12 months of follow-up (complete group: 23.9 ± 7.4 to 15.4 ± 5.1 mmHg (p < 0.01); POAG: 22.8 ± 6.5 to 15.1 ± 4.6 mmHg (p < 0.01); NTG: 16.6 ± 3.4 to 11.6 ± 2.2 mmHg (p < 0.05); PEX: 28.0 ± 7.9 to 17.1 ± 6.6 mmHg (p < 0.01); Sec.Gl: 28.9 ± 13.9 to 15.5 ± 6.9 mmHg (p < 0.05)). In the 153 eyes the average number of IOP-lowering drugs applied decreased from 2.6 ± 1.2 to 0.8 ± 1.3 12 months after surgery (p < 0.01). BCVA and mean deviation of automated standard perimetry remained stable in all groups during follow-up.

CONCLUSION

As in eyes suffering from POAG, IOP and number of IOP-lowering drugs applied can be effectively reduced by XEN implantation in eyes suffering from NTG, PEX and secondary glaucoma while leaving BCVA and visual field unchanged.

TRIAL REGISTRATION

Trial was registered at DRKS (registration number: DRKS00020800 , Registered 25.February 2020 - Retrospectively registered).

Morphology of partial-thickness macular defects: presumed roles of Müller cells and tissue layer interfaces of low mechanical stability

BACKGROUND

The pathogenesis of partial-thickness macular defects and the role of Müller glial cells in the development of such defects are not well understood. We document the morphological characteristics of various types of partial-thickness macular defects using spectral-domain optical coherence tomography, with the focus on tractional and degenerative lamellar holes, and discuss possible pathogenic mechanisms.

METHODS

A retrospective case series of 61 eyes of 61 patients with different types of partial-thickness macular defects is described.

RESULTS

Partial-thickness macular defects are caused by anteroposterior or tangential traction onto the fovea exerted by the partially detached posterior hyaloid and epiretinal membranes, respectively. Tractional elevation of the inner Müller cell layer of the foveola-without (outer lamellar holes, foveal pseudocysts) or with a disruption of this layer (tractional lamellar holes, macular pseudoholes)-produces an elevation of the inner layers of the foveal walls (nerve fiber layer to outer plexiform layer [OPL]) and a schisis between the OPL and Henle fiber layer (HFL). With the exception of outer lamellar holes, the (outer part of the) central outer nuclear layer and the external limiting membrane remain nondisrupted in the various types of partial-thickness defects. Degenerative lamellar holes are characterized by cavitations between the inner plexiform layer and HFL of the foveal walls; many cases have lamellar hole-associated epiretinal proliferation (LHEP). Proliferating cells of the disrupted Müller cell cone may contribute to the development of LHEP and fill the spaces left by degenerated photoreceptors in the foveal center.

CONCLUSIONS

It is suggested that morphological characteristics of partial-thickness macular defects can be explained by the disruption of the (stalk of the) Müller cell cone in the foveola and the location of tissue layer interfaces with low mechanical stability: the boundary with no cellular connections between both Müller cell populations in the foveola, and the interface between the OPL and HFL in the foveal walls and parafovea. We propose that the development of the cavitations in degenerative lamellar holes is initiated by traction which produces a schisis between the OPL and HFL, and enlarged by a slow and chronic degeneration of Henle fibers and bipolar cells.Trial registration retrospectively registered, #143/20-ek, 04/03/2020.

Two different populations of Müller cells stabilize the structure of the fovea: an optical coherence tomography study

PURPOSE

To document with spectral-domain optical coherence tomography the structural stabilization of the fovea and the sealing of outer macular defects by Müller cells.

METHODS

A retrospective case series of 45 eyes of 34 patients is described.

RESULTS

In cases of a cystic disruption of the foveola as in macular telangiectasia type 2 and vitreomacular traction, the Müller cell cone provides the structural stability of the fovea. In cases of a detachment or disruption of the Müller cell cone, e.g., in foveal pseudocysts, outer lamellar holes, and degenerative and tractional lamellar holes, Müller cells of the foveal walls may provide the structural stability of the fovea by the formation of a hyperreflective external limiting membrane (ELM) which bridges the holes in the central outer nuclear layer (ONL). Müller cells of the foveal walls and parafovea mediate the regeneration of the foveal architecture in cases of outer lamellar and full-thickness macular holes. The regeneration proceeds by a centripetal displacement of photoreceptor cell somata which closes the holes in the central ONL. The closure may be supported by the formation of a glial tissue band at the ELM which seals the hole.

CONCLUSIONS

The Müller cell cone provides the foveal stability in cases of a cystic disruption of the foveola. The structural stability of the outer foveal layers is mainly provided by the Müller cells of the foveal walls and parafovea; these cells also mediate the regeneration of the outer fovea in cases of a defect of the central ONL.

Individualized Significance of 24-Hour Intraocular Pressure Curves for Therapeutic Decisions in Primary Chronic Open-Angle Glaucoma Patients

Purpose

Diagnostic 24-hour intraocular pressure curves (IPC) are well established in the management of glaucoma. However, objective criteria for the IPC indication are lacking. The aim of this study was to evaluate the impact of individual patient characteristics and glaucoma-related parameters on therapy decisions after IPC and thus examine their relevance for glaucoma management.

Patients and Methods

Retrospective analysis of adult primary open-angle glaucoma (POAG) patients who underwent an IPC (≥6 IOP measurements in 24 hours). The main exclusion criterion was previous IOP-lowering surgery. IPC-dependent (eg, mean and peak IOP) and IPC-independent parameters (eg, perimetry, RNFL thickness) were analyzed in relation to the therapeutic decision after IPC. Further, these parameters were compared in patient subgroups based on age, glaucoma stage, or therapy intensity.

Results

A total of 101 eyes of 101 patients were included. In general, mean and peak IOP were elevated in patients with a therapeutic change after IPC. These subjects presented differences of IPC-independent parameters (eg, IOP at admission, RNFL thickness, glaucoma stage). Regression analysis results suggested a predictive role of IPC-independent parameters for IPC therapeutic decisions. In subgroups of patients of older age or advanced glaucoma, IPC-independent parameters did not correlate with therapeutic decisions after IPC.

Conclusion

These results support the relevance of IPC in the therapeutic management of POAG. Moreover, the study promotes a personalized classification of patients using selected glaucoma characteristics to objectivize their individual benefit from IPC. Further prospective studies are needed to verify the utility of these parameters and IPC in the management of glaucoma.

Different modes of foveal regeneration after closure of full-thickness macular holes by (re)vitrectomy and autologous platelet concentrate

AIM

To describe using spectral-domain optical coherence tomography the regeneration of the foveal morphology after pars plana (re)vitrectomy surgery and gas tamponade combined with injection of autologous platelet concentrate to treat full-thickness macular holes, and to describe different anatomical outcome.

METHODS

A retrospective case series of 8 eyes of 8 patients was described.

RESULTS

In all cases investigated, the platelet-assisted closure of macular holes was associated with a rapid resolution of cystic cavities in the foveal walls. In two patients, there was a regular regeneration of the foveal morphology after hole closure; the regenerated central fovea had a regular structure with a foveola and photoreceptors. In three other patients, there was an irregular regeneration of the fovea; a foveola was not formed, photoreceptor cells were absent from the foveal center, and the center was composed of Müller and retinal pigment epithelial (RPE) cells. The foveal regeneration after hole closure may proceed with or without a temporary detachment of the foveal center from the RPE, and with or without a direct contact between the central outer nuclear layer (ONL) and the RPE. Contacts between the ONL and RPE were observed only in patients with an irregular foveal regeneration after hole closure.

CONCLUSION

The data show that there are different modes of foveal regeneration after closure of macular holes with (re)vitrectomy and platelet concentrate. It is suggested that the regular regeneration of the foveal morphology proceeds by Müller cell-mediated tissue movements without cell proliferation, whereas the irregular foveal regeneration proceeds in part by proliferation of Müller and RPE cells.

[Secondary Neuroprotection in Glaucoma by Reduction of Intraocular Pressure]

The central goal of glaucoma treatment is the reduction of intraocular pressure (IOP) by means of medication and/or surgery, in order to prevent further disease progression for as long as possible. Stabilising visual field defects and saving papillary neural tissue are seen as the optimal achievable aims in glaucoma therapy. We performed a systematic literature search and analysis of the published articles dealing with neuroprotection and functional improvement by IOP reduction in glaucoma. On this basis, the known options for anatomical and functional recovery of formerly lost structures and functions will be elucidated. Several studies - some large - have provided evidence for anatomical improvement at the optic nerve head and functional improvement in the results of visual field tests. After glaucoma treatment, there is anatomical and functional improvement in some patients. However, improvement is mostly detectable in patients whose IOP was greatly reduced.

Prognostic Factors in Patients with Persistent Full-Thickness Idiopathic Macular Holes Treated with Re-Vitrectomy with Autologous Platelet Concentrate

PURPOSE

To identify the predictors for anatomical and functional outcome after re-vitrectomy with application of autologous platelet concentrate (APC) in eyes with persistent idiopathic macular hole (MH).

METHODS

Retrospective study of 103 eyes with persistent MHs after vitrectomy with peeling of internal limiting membrane (ILM) and expansive gas. All patients underwent re-vitrectomy with APC and endotamponade. The anatomical MH closure rate and postoperative best-corrected visual acuity (BCVA) were evaluated. Further, predictive factors influencing the success of the surgery were analyzed.

RESULTS

Median BCVA (logMAR) before the surgery was 1.00 (interquartile range [IQR] 0.80-1.30) and the median of minimum diameter between hole edges was 508 µm (IQR 387-631). The final closure rate after re-vitrectomy with APC was 60.2% (62 of 103 eyes). The following predictors were identified to significantly influence the closure rate: tractional hole index (THI), axial length, time between first and second surgery, and the experience of the surgeon (p < 0.05).

CONCLUSIONS

Re-vitrectomy with APC led to the closure of 60.2% of the persistent MHs. The closure rate negatively correlates with increasing axial length, time between the first and second surgery, and the decreased THI. Further, experienced surgeons (with a history of >100 pars plana vitrectomies with ILM peeling) had significantly higher closure rates.

Real-world outcomes of observation and treatment in diabetic macular edema with very good visual acuity: the OBTAIN study

AIMS

To describe and compare the functional and anatomical outcomes of untreated and treated diabetic macular edema (DME) in eyes with very good baseline visual acuity (VA) in a real-world setting.

METHODS

A 12-month, retrospective, multicenter, observational cohort study, including DME patients with baseline visual acuity (VA) ≤ 0.1 logMAR (≥ 20/25 Snellen) and central subfield thickness (CST) > 250 µm with intra- and/or subretinal fluid seen on optical coherence tomography.

RESULTS

A total of 249 eyes were included, of which 155 were treated and 94 were non-treated during follow-up. Most eyes maintained vision (VA gain or VA loss < 5 letters) at 12 months (treated: 58.1%; non-treated: 73.4%). In non-treated eyes with stable VA within the first 6 months, VA was maintained throughout the follow-up in most cases (86.3%). In non-treated eyes with VA loss ≥ 5 letters within 6 months (36.7%), further observation led to worse visual outcome than treatment (- 4.2 vs. - 7.8 letters, p = 0.013). In eyes in which treatment was initiated at baseline (n = 102), treatment with 8-12 anti-VEGF injections led to better visual outcome compared to treatment with less injections (- 0.3 ± 3.6 letters vs. - 3.8 ± 6.2 letters, p = 0.003).

CONCLUSION

In a real-world setting, the majority of DME patients with very good VA maintained vision at 12 months, regardless of whether the DME was treated or not. This study supports close observation of eyes with DME and very good VA with consideration of treatment when a one line drop in vision is observed.

[DMEK à chaud]

PURPOSE

This article reports a case of unintended excision of Descemet's membrane (DM) during a routine cataract extraction (CE), which was successfully treated by Desecemet membrane endothelial keratoplasty (DMEK).

MATERIAL AND METHODS

During routine CE of a 91-year old male patient the DM was almost completely detached and excised.

RESULTS

The DMEK was successfully performed, the cornea cleared and visual acuity increased from cc 0.02 to cc 0.8.

CONCLUSION

Unintended excision of DM can be successfully treated by DMEK at short notice.

Comparing the efficacy of trabeculectomy and diode laser cyclophotocoagulation in primary open-angle glaucoma

PURPOSE

The aim was to compare the postsurgical outcomes of trabeculectomy (TET) and transscleral cyclophotocoagulation (CPC) in a similar cohort of eyes diagnosed with primary open-angle glaucoma (POAG).

MATERIALS AND METHODS

For this monocentric non-randomized retrospective comparative trial, the records of eyes which underwent TET or CPC between 2013 and 2016 at our institution for the treatment of POAG were reviewed. Parameters analyzed before surgery as well as 1 and 2-3 years afterwards were visual acuity (VA), intraocular pressure (IOP), mean defect (MD) of the visual field, number of glaucoma medications and the objective refraction using which the surgically induced astigmatism (SIA) was calculated.

RESULTS

In total, 51 eyes of 51 patients underwent TET and 45 eyes of 45 patients underwent CPC. Mean VA dropped in both groups on the last follow-up after surgery (TET-group: 0.17 ± 0.17 to 0.23 ± 0.28 logMAR, p = 0.01/CPC-group: 0.22 ± 0.22 to 0.26 ± 0.27 logMAR, p = 0.01). In the TET- and CPC-groups IOP decreased significantly (TET: 24.9 ± 6.4 to 14.9 ± 3.1 mmHg, p = 0.001/CPC: 23.0 ± 6.5 to 16.0 ± 4.1 mmHg, p = 0.001) although more pronounced and less depending on IOP-lowering medication in eyes after TET. MD remained stable after TET (7.4 ± 4.8 and 8.1 ± 4.9 dB, p = 0.1) but further deteriorated in eyes after CPC (9.0 ± 4.9 and 10.7 ± 4.6 dB, p < 0.001). SIA was comparable in both groups on the last follow-up (TET: 0.83 ± 0.69 D; CPC: 0.91 ± 0.65 D, p = 0.6).

CONCLUSION

The IOP reduction achieved without medication was more pronounced in the TET-group compared with the CPC-group. Visual field remained stable in the TET-group, while further deteriorating in the CPC-group during follow-up. Eyes undergoing CPC had a higher demand for additional medication to reach comparable success rates as TET. Due to this performing TET is favorable over CPC in POAG eyes.

[Analysis of Glaucomatous Changes of the Macula Using Optical Coherence Tomography]

BACKGROUND

In glaucoma, progressive retinal nerve fibre loss can be measured in the peripapillary and macular regions using optical coherence tomography (OCT). The goal of this study was to evaluate the impact of glaucoma on all measureable retinal layers using the spectral domain OCT (SD-OCT).

MATERIALS AND METHODS

SD-OCT scans using automated retinal layer segmentation were performed in both eyes of primary open-angle glaucoma patients with strictly monocular absolute visual field scotoma in the central 10° of their visual field. The same measurements were performed in one eye per person in a healthy age-matched control group. The mean thickness of all retinal layers in the central 24 × 24° of the macular region was compared between groups.

RESULTS

SD-OCT scans were performed in 24 eyes of 12 glaucoma patients (10 female, 2 male) with a mean age of 72.3 ± 8.1 years and in 12 eyes of 12 healthy controls (9 female, 3 male) with a mean age of 66,0 ± 7,6 years. Statistically significant thickness differences between the glaucomatous and the healthy eyes could be demonstrated for the retinal nerve fibre layer, the ganglion cell layer, the inner plexiform layer and the complete retinal thickness, with lower mean thicknesses in the glaucoma group.

CONCLUSION

Using SD-OCT, single retinal layers of the macular region can be scanned and measured automatically. In glaucoma, a decrease in thickness of the inner retinal layers containing ganglion cells and their axons or dendrites could be demonstrated compared to healthy eyes. No corresponding difference in thickness could be found for the outer retinal layers using SD-OCT measurements.

Müller Cell-Derived PEDF Mediates Neuroprotection via STAT3 Activation

Background/ Aims: This study was performed to reveal signaling pathways exploited by pigment epithelium-derived factor (PEDF) derived from retinal (glial) Müller cells to protect retinal ganglion cells (RGCs) from cell death.

METHODS

The survival of RGCs was determined in the presence of conditioned culture media (MCM) from or in co-cultures with Müller cells. The significance of PEDF-induced STAT3 activation was evaluated in viability assays and using Western blotting analyses and siRNA-transfected cells.

RESULTS

Secreted mediators of Müller cells increased survival of RGCs under normoxia or hypoxia to a similar degree as of PEDF- or IL-6-exposed cells. PEDF and MCM induced an increased STAT3 activation in RGCs and R28 cells, and neutralization of PEDF in MCM attenuated STAT3 activation. Inhibition of STAT3 reduced PEDF-promoted survival of RGCs. Similar to IL-6, PEDF induced STAT3 activation, acting in a dose-dependent manner via the PEDF receptor (PEDF-R) encoded by the PNPLA2 gene. Ablation of PEDF-R attenuated MCM-induced STAT3 activation and compromised the viability of PEDF-exposed R28 cells.

CONCLUSIONS

Müller cells are an important source of PEDF, which promotes RGC survival through STAT3 activation and, at least in part, via PEDF-R. Enhancing the secretory function of Müller cells may be useful to promote RGC survival in retinal neurodegenerative diseases.

[Protective Effects of Müller Glia Cells Towards Retinal Ganglion Cells]

INTRODUCTION

Müller glial cells carry out different tasks to warrant normal retinal functions. The aim of this study was to investigate if Müller cells also support retinal ganglion cells (RGC).

MATERIALS AND METHODS

RGC were cultured for 24 hours in the presence or absence of Müller glial cells under normoxic (20% O₂, 5% CO₂) or hypoxic (0.2% O₂, 5% CO₂, 94.8% N₂) culture conditions. The number of vital RGC and the length of the newly developed neurites were evaluated.

RESULTS

Under normoxic conditions, RGC vitality was significantly higher (p < 0.01) when cultured with Müller cells (62.85 ± 2.06%) than without (47.29 ± 2.83%). Under hypoxia, RGC vitality was significantly higher (p < 0.01) in co-cultures (41.07 ± 2.28%) than in homotypic RGC cultures (28.49 ± 2.16%). The maximum length of the newly developed neurites was found in the normoxic co-culture (90.7 ± 7.4 µm), but showed only a minor difference (p = 0.04) when compared to the normoxic homotypic RGC culture.

CONCLUSION

Müller glial cells support RGC under normoxic and hypoxic culture conditions. Length of newly developed neurites and number of surviving RGC are both parameters to evaluate cell vitality.

[Bilateral eye injuries by external transversal force]

A 49-year-old female victim of violent crime with an acute bilateral loss of vision was referred to our hospital. The ophthalmological evaluation showed complete subconjunctival hemorrhage of both eyes, bilateral hemophthalmos and hypotonia of the left eye. These raised the suspicion of an occult scleral rupture. We immediately performed exploratory surgery and found a perforating scleral lesion of the left eye and a penetrating scleral lesion of the right eye. Furthermore, a small, cruciform wound was detected on the left temple. In cooperation with the department of radiology, the extraordinary injury pattern was reconstructed: a horizontal stab wound with perforation of the left eye and penetration of the right eye caused by a screwdriver. Visual rehabilitation necessitated further surgical interventions. Besides the intraoperative approach, immediate primary wound management within 100 h of trauma plays a pivotal role for long-term outcome.

Enhanced survival of retinal ganglion cells is mediated by Müller glial cell-derived PEDF

The death of retinal ganglion cells (RGC) leads to visual impairment and blindness in ocular neurodegenerative diseases, primarily in glaucoma and diabetic retinopathy; hence, mechanisms that contribute to protecting RGC from ischemia/hypoxia are of great interest. We here address the role of retinal glial (Müller) cells and of pigment-epithelium-derived factor (PEDF), one of the main neuroprotectants released from the glial cells. We show that the hypoxia-induced loss in the viability of cultured purified RGC is due to apoptosis, but that the number of viable RGC increases when co-cultured with Müller glial cells suggesting that glial soluble mediators attenuate the death of RGC. When PEDF was ablated from Müller cells a significantly lower number of RGC survived in RGC-Müller cell co-cultures indicating that PEDF is a major survival factor allowing RGC to escape cell death. We further found that RGC express a PEDF receptor known as patatin-like phospholipase domain-containing protein 2 (PNPLA2) and that PEDF exposure, as well as the presence of Müller cells, leads to an activation of nuclear factor (NF)-κB in RGC. Furthermore, adding an NF-κB inhibitor (SN50) to PEDF-treated RGC cultures reduced the survival of RGC. These findings strongly suggest that NF-κB activation in RGC is critically involved in the pro-survival action of Müller-cell derived PEDF and plays an important role in maintaining neuronal survival.

[Firework-related eye trauma from 2005 to 2013]

PURPOSE

Fireworks combusted during New Year's Eve festivities can cause different eye traumas which often need complex reconstructive surgery. It was our aim to systematically analyse these eye trauma cases which were treated at our clinic during the last eight years.

MATERIALS AND METHODS

Age, gender, side, trauma mechanism, treatment methods and outcome were analysed for all eye trauma cases caused by fireworks during the New Year's Eve celebrations from 2006 to 2013. For statistical analysis all trauma cases were divided into two groups of major and non-major eye trauma.

RESULTS

The total number of patients treated was 122 (28 women, 94 men, mean age 26.2±13.0 years) with 137 traumatised eyes (77 right, 60 left). 24.6% of patients were ≤18 years of age. 76.2% were bystanders. 50 eyes from 46 patients (37.7%) suffered from major eye trauma. 26 patients (21.3%) were hospitalised. 8 eyes (5.8%) suffered from a penetrating injury or globe rupture and underwent primary reconstructive surgery. Further 16 eyes (11.7%) suffered from major eye trauma without open globe injury. In the aftermath 11 eyes (8.0%) went blind (visual acuity<1/50). Gender, side and role of the patient were not significantly different between the two groups. Mean age was significantly higher in the major eye trauma group (p=0.01).

CONCLUSION

Young male bystanders have a high risk for suffering from eye trauma caused by fireworks. However older patients suffer from major eye trauma more often. More education and prophylaxis of eye trauma caused by fireworks is desirable.

[Scheimpflug photography of acute angle closure]

PURPOSE

In acute angle-closure glaucoma a laser iridotomy (IO) is performed to balance the intraocular pressure between the anterior and posterior chambers. The changes induced in the anterior chamber architecture were analyzed using Scheimpflug photography.

MATERIAL AND METHODS

Scheimpflug photography was performed in eyes with acute angle closure and in the contralateral eyes before and after IO.

RESULTS

In a group of 10 patients (8♀, 2♂, average age71.2 ± 5.3 years) 10 eyes with acute angle closure and 10 contralateral eyes were analyzed. The anterior chamber depth, central corneal thickness and anterior chamber angle did not change significantly after IO. The mean anterior chamber volume showed a statistically significant increase in the 10 eyes with acute angle closure and in the 10 contralateral eyes.

CONCLUSION

Anterior chamber volume increases due to IO but not anterior chamber depth, central corneal thickness and anterior chamber angle in eyes with acute angle closure.

Pigment epithelium-derived factor released by Müller glial cells exerts neuroprotective effects on retinal ganglion cells

Survival of retinal ganglion cells (RGC) is compromised in several vision-threatening disorders such as ischemic and hypertensive retinopathies and glaucoma. Pigment epithelium-derived factor (PEDF) is a naturally occurring pleiotropic secreted factor in the retina. PEDF produced by retinal glial (Müller) cells is suspected to be an essential component of neuron-glial interactions especially for RGC, as it can protect this neuronal type from ischemia-induced cell death. Here we show that PEDF treatment can directly affect RGC survival in vitro. Using Müller cell-RGC-co-cultures we observed that activity of Müller-cell derived soluble mediators can attenuate hypoxia-induced damage and RGC loss. Finally, neutralizing the activity of PEDF in glia-conditioned media partially abolished the neuroprotective effect of glia, leading to an increased neuronal death in hypoxic condition. Altogether our results suggest that PEDF is crucially involved in the neuroprotective process of reactive Müller cells towards RGC.

Comparison of dynamic contour tonometry and Goldmann applanation tonometry in keratoconus

PURPOSE

We performed a comparative study using Goldmann applanation tonometry (GAT) and dynamic contour tonometry (DCT) to measure intraocular pressure (IOP) in eyes with keratoconus.

METHODS

IOP was measured in 114 eyes of 75 patients with keratoconus (51 men and 24 women; mean age, 36.1 ± 11.2 years) using GAT and DCT in randomized order. Central corneal thickness (CCT), minimal corneal thickness (MCT), and corneal topography were recorded using the Pentacam. Four groups according to Amsler's keratoconus classification were composed and analyzed for significant differences of CCT, MCT, GAT, and DCT results.

RESULTS

Mean CCT in the 114 keratoconus eyes was 481.1 ± 46.2 μm (range, 334-601 μm). Mean MCT was 453.3 ± 56.3 μm (range, 239-573 μm). Mean IOP measured using GAT was 13.1 ± 2.9 mm Hg, whereas mean IOP measured using DCT was 14.8 ± 2.6 mm Hg. Neither the results for GAT nor those for DCT showed a significant correlation with CCT (Pearson correlation: P < 0.05). Multifactorial analysis revealed that CCT and MCT, but not GAT and DCT, results were significantly different in corneas of varying curvatures.

CONCLUSIONS

This study shows that DCT measures IOP higher than GAT in eyes with keratoconus. In keratoconus, both methods seem to be independent of CCT and therefore are equally, but not interchangeably, applicable when monitoring IOP. Further analysis revealed that CCT and MCT are significantly different in corneas of varying Amsler grade.

[1-year results after posterior lamellar keratoplasty with manually dissected donor tissue]

OBJECTIVE

Posterior lamellar keratoplasty (PLK) is a reasonable alternative to penetrating keratoplasty (PK) for pathological changes of the corneal endothelium. The lamellar preparation of the donor tissue can be done in an automated fashion with a microkeratome, Descemet Stripping Automated Keratoplasty (DSAEK) or manually, Descemet Stripping Endothelial Keratoplasty (DSEK). Here, we describe our clinical results with one year follow-up using manually dissected donor lamellae for PLK.

METHODS

For 28 eyes (28 patients) best-corrected visual acuity, corneal topography, esthesiometry, pachymetry, as well as endothelial cell count were measured before, 1 day, 1 and 6 weeks, as well as 3, 6 and 12 months after surgery.

RESULTS

3 of 28 grafts showed primary graft failure. For 19 eyes (no other vision-limiting diseases), the best-corrected visual acuity rose on average from 1.0 +/- 0.53 to 0.4 +/- 0.20 (logMAR) 1 year after surgery. The surgically induced astigmatism changed from 3.8 +/- 2.8 dpt preoperatively to 1.4 +/- 1.0 dpt 12 months after DSEK. The pachymetry measured by slit lamp showed an averaged thickness of 649 +/- 54 mm pre- and 776 +/- 75 mm one week and 636 +/- 79 mm 1 year after surgery was performed. The endothelial cell count of the grafts was 2615 +/- 156 cells/mm (2), after one year postoperatively the mean endothelial cell count was 2084 +/- 536 cells/mm (2). The esthesiometry showed a slight rise from 0.96 +/- 0.34 g/mm (2) pre- to 0.96 +/- 0.03 g/mm (2) one year post-surgery.

CONCLUSIONS

The postoperative course of our patients shows that improvement of visual acuity by PLK with manually dissected donor tissue is possible.